1. Field of the Invention
The present invention relates to data processing apparatus and more particularly to apparatus for processing information data such as moving image data and audio data by means of playback description data.
2. Description of the Related Art
Apparatus for processing digital image data such as digital videotape recorders and DVD (digital versatile disc) players have become common in recent years. Advances in various audiovisual equipment and computers have also made it possible for amateurs to edit moving images at home.
For example, in a video editing scheme called nonlinear editing as shown in FIG. 13, material data of moving images A 1301 and B 1302 are edited to obtain moving image C 1303. Thus, in the conventional non-linear editing scheme, material moving image data are generally cut-in or cut-out along the time axis, rearranged, or given various effects such as a wipe between cuts, thereby rendering the image and creating new moving image data.
Since the moving image data typically contains a great amount of information, it is in many cases compressed or encoded. When editing such compressed or encoded material data, the data is first decoded, edited and then encoded again.
In recent years, description languages have been proposed for controlling the playback processing of the moving image data or audio data.
An example is the SMIL (synchronized multimedia integration language). The SMIL can specify a synchronous and a consecutive playback of such image data as moving image and stationary image, and a playback processing of other media data including text and audio. It can also specify special effects applied during the switching of image data displays, for example.
In the conventional non-linear editing scheme, additional effects such as wipe and dissolve are effected directly on the image data. This makes it impossible to remove only the added effect or to replace with a different effect later. The scheme is also unable to distinguish the material portion and the portion to which the additional effect processing as been provided.
The playback description languages can be used in adding video effects, the contents of which can be exchanged by rewriting the playback description language.
However, even though the playback description languages such as the SMIL can freely describe playback procedures and special effects, it is sometimes impossible to perform a playback as specified, depending on the actual playback environment in which the playback processing is performed. For instance, some playback environments may hinder a real-time execution of a described special effect and thus disregard the description about the special effect.
Thus, no description schemes have been available which enable the description of highly sophisticated and complex video effects.